Most horizontal vehicle lifts are fixed structures intended for use in commercial garages. Such lifts are wider than the vehicles to be lifted. Typically, garage lifts have a lift height of at least 1.5 m and are powered by electric motors or hydraulic pressure. Commercial 1- to 4-post lifts are too wide, require too much headroom and are too expensive for general use, as well as being a fixed structure.
Alternative methods of raising a vehicle in a horizontal configuration include an elevated platform accessed by long ramps, which occupy excessive space both when attached to the elevated platform and, if detachable, when stored. Other methods include drive-on ramps which can then be tilted to a horizontal configuration. Such tilting lifts are inherently unstable and therefore require reliable locking mechanisms. These and other more complicated ramp lifts are generally too expensive, too heavy or too large for domestic use, or may have structures that limit access underneath a vehicle.
Many people attempt to raise the vehicle using a lifting jack, with or without axle stands or blocks to maintain the vehicle in an elevated position. This is potentially dangerous if one wishes to work underneath the vehicle and is difficult if one needs to elevate more than one wheel at the same time.
Another problem arises if a vehicle's ground clearance is less than the minimum height of the jack.
There is a need for a small lift to enable a person to work underneath a vehicle in a domestic garage or small workshop, or at the roadside. For this purpose, the possibility of raising a vehicle some 350 mm above its normal ground clearance gives good access to the underside, while reducing the risks of backache when working on the wheels, brakes, suspension, engine, interior and topsides.
U.S. Pat. No. 6,464,204 dated 15 Oct. 2002, of Danny L. Johnson et al. and assigned to Kwiklift, Inc., describes and claims a portable vehicle lifting apparatus comprising a pair of ramps pivoted at one end to base units and having a lifting bar pivotally connected between each ramp. The pivotal connection between the lifting bar and the ramps adds an additional complexity to the apparatus. When using a single jack, if the lifting force is offset from the centre line of the lifting bar, additional locking mechanisms are required to prevent rotation of the lifting bar. Also, in the absence of features to constrain the lifting force to the mid-span of the lifting bar, there may be a tendency for the ramps to twist relative to each other.
BE 509211 dated 29 Feb. 1952 of C. Hosay describes a similar apparatus to U.S. Pat. No. 6,464,204 but with no provision for a jack being used to elevate the ramps.